Tube shield



H. J. MURPHY Sept. 1, 1959 TUBE SHIELD Filed July 1a, 1956 ATTORNEY United States Patent TUBE SHIELD Howard J. Murphy, North Wilmington, Mass, assignor to United-Carr Fastener Corporation, Boston, Mass,

a corporation of Delaware Application July 13, 1956, Serial No. 597,727

8 Claims. (Cl. 174-35) The present invention relatesto an improved electrical shield construction, and more particularly to an improved tube shield construction for association with electron discharge tubes or the like in electrical apparatus to avoid undesirable reactions between the various elements thereof.

-A wide variety of shielding means, generally identified as tube shields, have been employed heretofore in electrical-apparatus, such as, for example, radio sets, to dissipate electro-magnetic and electrostatic fields set up therein by the electron discharge tubes during the operation-of the apparatus. While such prior tube shields adequately perform their intended shielding function, such tube shields have possessed many disadvantages which have been found objectionable.

. One of the most common forms of tube shields heretofore employed has consisted of a simple can or cylinder which is secured to the chassis in detachable relationship therewith by a friction fit or similar fastening means. When a tube is to be replaced in an apparatus employing theso-called can type tube shield, the tube shield is completely detached from the chassis of the apparatus, after which the tube is then replaced. Oftentimes the repairman or technician performing the operation will fail: to replacethe tube shield with a corresponding impairment in the operation of the apparatus. Moreover, the failure to replacethe tube shield invariably results in the tube shield being left on the chassis, thereby resulting in .the likelihood of a short circuiting of the electrical apparatus. Another disadvantage with the can type .tube shield is that the continued insertion and withdrawal of the tube shield from time to time during thereplacement results in a loose connection between the tube shield and the chassis. This will result in a vibration of the tube shield, oftentimes not insuring a positive grounding of the shield to the chassis.

Another detachable form of the tube shield that has received widespread usage is the so-called shaped shield. This type consists of two symmetrically paired parts of sheet metal and shaped to fit closely to the bulb of the tube. The paired parts are held together by a detachable ring; a detachable collar, or various other forms of clamping and connecting parts. Such shaped tube shields, in addition to the basic disadvantages attendant todetachable tube shields in general, suffer further in that all tubes arenot one size. Therefore, several different sizes must be made and stocked, resulting in an unnecessary inventory. Moreover, the design and multiplicityiof parts of the shaped tube shields have resulted in a relatively high cost for such shields.

Somc attempts have been made to eliminate these disadvantages attendant to the various forms of detachable tube shields fixedly securing the tube shields to the chassis. Such fixed tube shield constructions have consisted of two mating or paired parts, each of which are hingedly connected at their bottom ends to one another or to the chassis. To replace a tube in an electrical apparatus employing such a construction, each of the mating parts is pivoted upwardly away from one another, the tube then replaced, and the component parts then pivoted inwardly to one another to envelope and shield the new tube. A principal disadvantage with this type of tube shield is that it is extravagant of chassis space and does not permit the positioning of the tubes to the manufacturers requirements. Another disadvantage with disadvantages attendant to previously employed tube shields.

Another object of the present invention is the provision of an improved tube shield construction which will permit replacement of a tube more easily than with prior tube shields.

Yet another object of the present invention is the provision of an improved tube shield construction which will be permanently affixed to the chassis, thereby in suring the proper functioning of the tube shield at all times.

' A further object of the present invention is the pro-' vision of an improved tube shield construction that requires a minimum amount of chassis space.

A still further object of the present invention is the provision of an improved tube shield construction inwhich the component parts will be in proper engagement with one another at all times.

Another object of the present invention is the provision of an improved'tube shield construction that will remain in tight engagement and in proper grounded relationship with the chassis at all times.

A still further object of the present invention is the provision of an improved tube shield construction that is of extreme simplicity in design and operation, and inexpensive to manufacture.

Other and additional objects will become apparent from the ensuing description taken in conjunction with the accompanying drawings.

Broadly stated, in the attainment of the foregoing and related advantages, the tube shield construction of the present invention comprises inner and outer sleeve means, said inner sleeve means having connecting means positioned at one end thereof for securing same to a support infixed relationship thereto, and a plurality of outwardly flared flexible finger means extending upwardly from the opposite end thereof in general longitudinal alignment therewith, said outer sleeve means being of a height less than that of the inner sleeve means, and being slidable longitudinally with respect thereto.

To the accomplishment of the foregoing and related ends, the present invention then consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain means in the carrying out of the invention, such disclosed means illustrating, however, but one of various ways in which the principle of the invention may be employed.

The present invention is illustrated by way of example in the accompanying drawings, in which: i

Figure l is a perspective view of outer sleeve means forming a component part of a tube shield construction made in accordance with the present invention.

Figure 2 is a perspective view of the inner sleeve means I to be associated with said outer sleeve means to form a tube shield construction made in accordance with the present invention.

Figure 3 is a perspective view of a tube shield construc tion made in accordance with the present invention with the outer shield in lowered position to permit the insertion or withdrawal of a tube.

Fgure 4 is a perspective view of a tube shield construction made in accordance with the present invention illustrating the outer sleeve means in raised position to provide the desired shielding.

Reference is now to be had to the drawing wherein an illustrative embodiment of a tube shield construction made in accordance with the present invention and generally indicated by reference numeral is shown. The tube shield construction 10, as illustrated, comprises an outer tubular sleeve member A partially enveloping a fixed inner tubular sleeve member B and being slidable longitudinally with respect thereto.

The outer tubular sleeve member A, as shown in Fig. 1, comprises a body portion 11 of a diameter greater than that of the tube to be shielded, and having a bottom, outwardly extending, circumferentially flanged portion 12 secured at one end thereof, and a top, outwardly extending, circumferentially flanged portion 13 secured at the opposite end thereof. The height of the body portion 11 is less than that of the electron discharge tube to be shielded, and preferably is of a height approximately one-half that of the tube in order to permit the ready withdrawal or insertion of a tube in a manner to be more fully described hereinafter. However, it is to be clearly understood that the height of the body portion may vary depending upon the height of the inner tubular sleeve member B, since it is the combination of the two that ,will provide the desired shielding.

The flange 13 serves to facilitate digital movement of the sleeve A relative to the fingered sleeve B, and as a stiffening means for the sleeve A. The lower flange portion 12, in the form shown, is identical with the upper flange portion 13 and serves the same stiffening function, the identity of these parts permitting the outer sleeve member A to be associated with the inner sleeve member B with either of the flange portions 12 and 13 functioning as digital contact means. j

The outer tubular sleeve member A may be made from any suitable metal that is capable of possessing some degree of flexibility, but yet has sufficient strength to resist bending or distortion in ordinary use. The outer sleeve member A may be made in any desired manner, and preferably is formed from a flat blank of sheet metal which is rolled to the required diameter, with the free ends overlapping one another circumferentially along the joining line lid-14a.

The inner tubular sleeve member B, as shown in Fig. 2 is of a height and diameter suificient to envelope the electron discharge tube to be shielded, although the diameter of the sleeve member B should be just slightly less than that of the outer sleeve member A so as to permit the outer sleeve member A to be in slidable, longitudinal, and rotatable engagement therewith without creating unnecessary distortional strain of the parts. The inner tubular sleeve member B comprises a lower body portion 15 having a plurality of circumferentially spaced, flexible finger portions 16 extending upwardly from one end thereof in slightly outwardly flared relationship, and in general longitudinal alignment therewith. The degree of flaring of the finger portion 16 is such that when compressed inwardly by engagement with the outer sleeve member A in a manner to be more fully described hereinafter, the outer sleeve member A will be held in a fixed raised position. The upper free end of each of the finger portions 16 is provided with an outwardly turned flange portion 17 which will engage the upper end portion 13 of the outer sleeve member A to provide the necessary stop means to prevent the outer sleeve member A from becoming disengaged from the inner sleeve member B when in a raised position. The height of the lower body portion 15 of the inner sleeve member B will be generally the same as the height of the body portion 11 of the outer sleeve member A.

The inner sleeve member B is provided with spaced lug portions 13 secured at the bottom free end of the lower body portion 15 on opposite sides thereof to permit the engagement and securing of the inner sleeve member B to a chassis or support plate C by means of screws or bolts 19. It is to be clearly understood that these securing means are illustrative in character only, since there are a wide variety of other available attaching means by which the inner sleeve member B may be secured to the chassis C. For example, in my copending application Serial No. 597,718, filed July 13, 1956, other securing means are described which may be utilized equally as well in the present invention.

The inner sleeve member B may be made from the same material and in the same manner as the outer sleeve member A. A preferred method, as hereinbefore stated, is to roll the sleeve member B from a flat metal blank to the desired diameter, with the free ends of the lower base portion 15 overlapping one another circumferentially along joining line 20.

To employ the tube shield construction 10, the inner sleeve member B is secured to the chassis C over the tube socket opening by means of the screws or bolts 19 passing through the openings in the lugs 18. To insert the outer sleeve member A over the inner sleeve member B, the finger portions 16 are circumferentially compressed inwardly to a point such that the outer sleeve member A may he slid downwardly thereover. The sliding downwardly of the outer sleeve member A is continued until it is in mating and enveloping relationship with the body portion 15 at which time the finger portion .16 will snap outwardly. This construction makes it impossible to remove the outer sleeve member A from the inner sleeve member B without substantially deforming the finger portions 16, which will be extremely unlikely in the normal operation of the tube shield construction 10. Similarly, the resiliency and degree of flaring of the finger portion 16 will always insure the retention of the outer sleeve member A when in a raised position.

To provide the necessary shield, the outer member A is slid upwardly causing an inward compression of the finger portion 16 until the upper tube end 13 engages the outwardly extending flange portions 17 of the inner sleeve member B. This will result in the outer sleeve member B being held in locked, raised position and in conjunction with the body portion 15 of the inner sleeve member B will provide the necessary shielding of the tube.

To replace an electron discharge tube into the tube shield construction 10, the outer sleeve member A is slid longitudinally downwardly with respect to the inner sleeve member B until the bottom flange portion 12 of the sleeve member A is in contact with the cars 18 of the inner sleeve member B. This movement will result in a circumferentially outward flaring of the resilient finger portions 16 of the inner sleeve member B leaving a large opening at the top for removal of the bad tube. The new electron discharge tube D is then inserted in the socket opening in the customary manner. To provide the necessary shielding of the electron discharge tube D, the outer sleeve member A is then grasped and slid upwardly over the resilient finger portions 16 causing their circumferentially inward compression until the flange portion 13 strikes the under surface of the flange portion 17 of the inner sleeve member B. At this point the outer sleeve member A will be held in a tight raised position and will completely shield the upper half of the electron discharge tube D, with the lower base portion 15 of the inner sleeve member B shielding the lower half, thereby forming a complete tubular shield for the electron discharge tube D. The resilient sliding friction engagement between the resilient fingers 16 and the sleeve A aflords a wiping contact between these parts insuring etfecti-ve grounding to the chassis C of the entire tube structure.

While there have been described herein what are at present Considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.

I claim:

1. A tube shield construction comprising inner and outer sleeve means, connecting means at one end of said inner sleeve means for securing same to a support in fixed relationship thereto, a plurality of outwardly flared flexible finger means extending upwardly from the opposite end of said inner sleeve means in general longitudinal alignment therewith, said outer sleeve means enveloping a portion of said inner sleeve means and being longitudinally movable with respect thereto, and stop means at the free ends of said finger means to retain the outer sleeve means on said inner sleeve means.

2. A tube shield construction comprising inner sleeve means, connecting means at one end of said inner sleeve means for securing same to a support, a plurality of outwardly flared flexible finger means extending upwardly from the opposite end of said inner sleeve means in generally longitudinal alignment therewith, outer sleeve means of a height less than that of said inner sleeve means circumferentially enveloping said inner sleeve means and being longitudinally movable with respect thereto, and stop means at the free ends of said finger means to retain the outer sleeve means on said inner sleeve means.

3. A tube shield construction comprising inner sleeve means, connecting means at one end of said inner sleeve means for securing same to a support, a plurality of outwardly flared flexible finger means extending upwardly from the opposite end of said inner sleeve means in generally longitudinal alignment therewith, outer sleeve means of a height less than that of said inner sleeve means circumferentially enveloping said inner sleeve means and being longitudinally movable with respect thereto, whereby the upward longitudinal movement of said outer sleeve means will result in the inward flexing of said finger means to retain the sleeve means in a raised position.

4. A tube shield construction comprising inner sleeve means, connecting means at one end of said inner sleeve means for securing same to a support, a plurality of outwardly flared flexible finger means extending upwardly from the opposite end of said inner sleeve means in generally longitudinal alignment therewith, outer sleeve means of a height less than that of said inner sleeve means circumferentially enveloping said inner sleeve means and being longitudinally movable with respect thereto, whereby the upward longitudinal movement of said outer sleeve means will result in the inward flexing of said finger means to retain the sleeve means in a raised position, and stop means at the free ends of said finger means to retain the outer sleeve means on said inner sleeve means.

5. A tube shield construction comprising inner sleeve means, connecting means at one end of said inner sleeve means for securing same to a support, a plurality of outwardly flared flexible finger means extending upwardly from the opposite end of said inner sleeve means in generally longitudinal alignment therewith, outer sleeve means of a height less than that of said inner sleeve means circumferentially enveloping said inner sleeve means and being longitudinally movable with respect thereto, said arm portions and the upper end of said outer sleeve means being provided with outwardly extending complementary stop means to retain the outer sleeve means on said inner sleeve means.

6. A tube shield construction comprising a first sleeve means provided at one of its ends with connecting means for securing same to a support and provided at its other end with a plurality of peripherally spaced longitudinally projecting spring fingers, a second sleeve means longitudinally slidable relative to said first sleeve means from a position proximate to said connecting means to a position proximate to the outer means of said spring fingers, and in the latter position shielding the spaces between said spring fingers, said spring fingers bearing resiliently against said second sleeve means for retaining it in an adjusted position, and stop means comprising outwardly extending flange portions carried by the outer end of said spring fingers and extending into the path of said second sleeve means for limiting the sliding movement of said second sleeve means.

7. A tube shield construction comprising a first sleeve means provided at one of its ends with connecting means for securing same to a support and provided at its other end with a plurality of longitudinally projecting spring fingers widely spaced peripherally to provide finger openings therebetween, a second sleeve means of a height at least equal to the length of said spring fingers and longitudinally slidable relative to said first sleeve means from a retracted position proximate to said connecting means to an extended position proximate to the outer ends of said spring fingers, said second sleeve means in said retracted position exposing the finger openings between said spring fingers for placement of fingers therebetween, and in said extended position shielding the spaces between said spring fingers thereby shielding the tube positioned therein, said spring fingers bearing resiliently against said second sleeve means for retaining it in adjusted position, and means to retain said second sleeve means with said first sleeve means.

8. A tube shield construction according to claim 7 wherein at least the end of said second sleeve means remote from said connecting means comprises outwardly extending flange means and said retaining means comprising outwardly turned flanged ends of said spring fingers overlying said flange means.

References Cited in the file of this patent UNITED STATES PATENTS 

